Most jurisdictions require operating brakes on towed vehicles if, when they are towed, they exceed certain weight limits. On our highways are hundreds of vehicles towing some kind of transportation vehicle used at destinations when towing vehicle is parked. Most of these towed vehicles exceed weight limits set by manufactures of motor homes in addition to state regulations, if self contained brakes are not operable when being towed.
Fines of up to $200 have been levied in Canada for not having brakes operating on a towed vehicle. They are also requiring operable emergency brakes as well. They require a towed vehicle not equipped properly to be disconnected and parked or driven while in Canada until terms of ordinance are complied with. (Trailer Life magazine article by Chuck Campbell November 96). Though our states are not yet enforcing operating brakes regulations for towed vehicles over specified weights the regulations are in place. Enforcement could begin anytime.
There are several patents intended to solve this problem. Some, however, are quite expensive and could not be easily installed by an owner, likely requiring an experienced mechanic's services. Several also require modifications of both towing and towed vehicle's D.O.T. approved brake systems. Those that depend on "surge action" (pushing movement of towed vehicle) are not recognized by the AMERICAN ASSOCIATION OF MOTOR VEHICLE ADMINISTRATION (a government agency that approves all brake systems in commercial use). Surge brakes are not allowed by Code 393.48a Federal Safety Regulation in B and C and are not permitted in commercial use. Surge brakes are not yet regulated for RVs.
Although the AMERICAN ASSOCIATION does not condemn modifications of brake systems, (they frown), they are concerned that extended lines and connections added to vehicles may cause contamination, e.g., air, moisture, or dirt to enter such systems. If one of these systems has a line fracture there would likely be a complete failure of both vehicle's system. A dependable assist system is needed that does not require changes in vacuum, hydraulic, or air lines of either vehicle. Such a system should provide emergency braking if a towed vehicle separates from towing vehicle. This invention will resolve both situations.
A patent search revealed the existence of several systems to assist towed vehicle braking;
U.S. Pat. No. 5,431,253 operates through an extended vacuum line.
U.S. Pat. No. 4,635,758 depends on an extended hydraulic line.
U.S. Pat. No. 4,174,869 has an interconnected hydraulic line.
U.S. Pat. No. 4,398,771 has vacuum line changes and added bellows.
U.S. Pat. No. 5,246,243 depends on a surge brake cylinder.
U.S. Pat. No. 5,411,331 depends on towed vehicle battery power to maintain air pressure. It also may use a radio signal or driver operated switch.
U.S. Pat. No. 4,280,737 has complicated electro-hydraulic system.
U.S. Pat. No. 5,000,519 is complicated by several switches for driver to remember.
These patents listed and others not listed are making modifications to D.O.T. approved brake systems. Though there are apparently no regulations restricting modifications, if a problem develops that is associated with some modification, someone could get into very serious litigation if a modified system fails and is proven to have caused an accident or serious injuries. It is quite possible that during connecting and disconnecting, contamination, moisture, dirt, air, could enter lines that are altered to adapt to these brake systems.
Some systems depend on radio signals, switches for a driver to decipher, a battery of a towed vehicle that could discharge while keeping an air compressor operating for a long driving period, or a suspended vacuum, air, or hydraulic line not rupturing. A ruptured line would cause complete failure of both vehicle's brake systems. A discharged battery could render a system useless without towing driver's knowledge.